That's totally up to PoolDoc and his schedule. If he gets tied up with something, as we all do, it can take a few days. Meantime, the mods and PF Support Team can see your threads and respond to your questions. Chem_Geek's knowledge of pool chemistry is second to none. I've been a mod here for Who Knows How Long and WaterMom's been here that long plus 5 or 10 more!
So we've seen a lot. Plus there are others on the support team who have lots of knowledge.